Impurities in biowaste, such as plastics, glass, metals and inert material, negatively impact the operation of anaerobic digestion plants and compost quality, and have to be removed prior to the anaerobic digestion process. Different mechanical pretreatments are available for this purpose. However, data on the removal efficiencies of pretreatment systems for different types of biowaste and for different kinds of impurities are still scarce. This study aims to determine the efficiencies for impurity removal of four biowaste pretreatment plants (BTPs) at real scale – (1) drum-screen + shredder + piston press; (2) shredder + piston press + screw press; (3) separation-mill; and (4) pulper + drum-screen. BTP 1 treats mixed food and garden wastes, while BTP 2, 3 and 4 treat mostly food waste. The efficiency of the pretreatment systems was influenced by the type of pretreated biowaste. The recovery of organics by the press was more efficient when pretreating food waste (BTP 2, 93%) than for treating mixed food and garden wastes (BTP 1, 77%). BTP 3 presented the highest recovery of biogas (up to 98%), but also the highest transfer of inert particles to the substrate. On the contrary, BTP 4 was the most efficient for the removal of inert particles; however, this system also presented 18% loss of biogas potential.

塑料，玻璃，金属和惰性材料等生物废物中的杂质会对厌氧消化设备的运行和堆肥质量产生负面影响，因此必须在厌氧消化过程之前将其清除。为此可以使用不同的机械预处理。但是，关于不同类型生物废物和不同种类杂质的预处理系统去除效率的数据仍然很少。这项研究旨在确定四家生物废物预处理厂（BTP）的实际去除杂质的效率–（1）滚筒筛+粉碎机+活塞压榨；（2）切碎机+活塞压机+螺旋压机；（3）分离机；（4）碎浆机+滚筒筛。BTP 1处理混合的食物和花园垃圾，而BTP 2、3和4处理大多数食物垃圾。预处理系统的效率受预处理生物废物类型的影响。在对食物残渣进行预处理（BTP 2，占93％）时，通过压机进行有机物的回收要比对食物和花园废弃物的混合处理（BTP 1，占77％）更有效。BTP 3的沼气回收率最高（高达98％），但惰性颗粒向基质的转移率最高。相反，BTP 4是去除惰性颗粒最有效的方法。但是，该系统还损失了18％的沼气潜力。相反，BTP 4是去除惰性颗粒最有效的方法。但是，该系统还损失了18％的沼气潜力。相反，BTP 4是去除惰性颗粒最有效的方法。但是，该系统还损失了18％的沼气潜力。